1. Technical Field
The present invention generally relates to a liquid crystal panel and a projector using the same, and more particularly to a liquid crystal panel with an adjustable lens array and a projector using the same.
2. Description of Related Art
Projectors are generally divided into transmission and reflective categories. During operation of a transmission-type projector, light emitted from a light source is separated into three color lights which are red (R), green (G) and blue (B) by a color separation optical system, and then the color lights R, G and B enter three liquid crystal panels in a one-to-one manner. The three liquid crystal panels modulate the color lights R, G and B respectively according to given image information. The modulated color lights R, G and B are combined by a cross dichroic prism and then are projected through a projection lens onto a screen to form a visible colored image.
The liquid crystal panel of the transmission-type projector generally comprises a thin film transistor (TFT) array, and a light transitive liquid crystal molecule layer which is controlled by the thin film array. Since the thin film transistor array is usually made of non-crystal material which is sensitive to photoemission, a black matrix is usually adopted in the liquid crystal panel to prevent light from directly irradiating on the thin film transistor array and to prevent contrast ratio reduction due to light leakage from a non-display area between pixels of the liquid crystal panel.
However, the presence of the black matrix results in the loss of incidence of light on the liquid crystal panel, and this leads to depravation of an aperture ratio and reduction of brightness of the liquid crystal panel. The aperture ratio means the ratio of an area through which the light passes to a total area of the liquid crystal panel. The higher the aperture ratio, the more the light passing through the liquid crystal panel. When the aperture ratio decreases, the screen becomes darker, resulting in lowered image quality.
In order to improve the aperture ratio of the liquid crystal panel, a micro-lens array (MLA) may be adopted to cooperative with the black matrix. Light which is blocked by the black matrix, is effectively converged onto the aperture of the pixels by the micro-lens array so as to improve the aperture ratio of the liquid crystal panel.
However, light modified by the micro-lens array enters the liquid crystal panel varying with a large angular difference, and this results in that the light to be emitted from the liquid crystal panel also has a large angular difference. As a result, the light emitted from the liquid crystal panel enters the projection lens with a large angular difference. There is a high possibility that light emitted from the liquid crystal panel with a large emission angle (this means a large incident angle to the projection lens), can not enter the pupil of the projection lens. This might cause problems like chrominance nonuniformities of the projected image, lowered contrast and reduced brightness of the projected image.